Question

Define primary and secondary productivity.

Hint:

Primary productivity = Energy by plants.
Secondary productivity = Energy transfer to herbivores and carnivores.

Answer 1

Primary productivity: The rate at which autotrophs (e.g., plants) convert sunlight into chemical energy (biomass).

Secondary productivity: The rate at which consumers convert organic material into their own biomass.

Primary productivity refers to the total energy fixed by autotrophs through photosynthesis. It includes:

• Gross primary productivity (GPP): Total energy produced.
• Net primary productivity (NPP): Energy available to herbivores after respiration losses.

Secondary productivity is the energy assimilated by consumers (herbivores, carnivores) from plant material.